476 research outputs found
Influence of La in xPBBiN of ternary nanoceramic composite (1-x)0.5PMN-0.5PZT-xPBBiN system by mechanic al activatio n technique for dielectric and piezoelectric properties
(1-x)[0.5Pb(Mg0.33Nb0.67)O3-0.5Pb(Zr0.53Ti0.47)O3]-x[Pb0.557Ba0.38La0.022Bi0.02Nb2O6] with both perovskite and tungsten bronze structured composite have been synthesized through mechanical activation technique. The strong influence of lanthanum addition to the lead-barium-bismuth-niobate (xPBLBiN) ceramics in perovskite structured (1-x)PMN-PZT on structural and functional properties is confirmed. X-ray diffraction patterns studies showed that these complex composites consisted of perovskite Cubic with tungsten bronze Orthorhombic phases. La modification in PBBiN of a ternary system (1-x)PMN-PZTxPBBiN revealed intensified orthorhombicity. As La increased the dielectric and piezoelectric properties tremendously increased in (1-x)PMN-PZT-xPBLBiN nanoceramic composite. The optimum dielectric and piezoelectric properties (εRT = 2931, kp = 0.461 and d33 = 428 pC/N) were found in x =0.4 composite. We achieved novel nanocomposites synthesized by high energy ball milling method and having binary structures in a single composite with excellent functional properties that can be used for energy harvesting applications
Joint Spectrum Sensing and Resource Allocation for OFDM-based Transmission with a Cognitive Relay
In this paper, we investigate the joint spectrum sensing and resource
allocation problem to maximize throughput capacity of an OFDM-based cognitive
radio link with a cognitive relay. By applying a cognitive relay that uses
decode and forward (D&F), we achieve more reliable communications, generating
less interference (by needing less transmit power) and more diversity gain. In
order to account for imperfections in spectrum sensing, the proposed schemes
jointly modify energy detector thresholds and allocates transmit powers to all
cognitive radio (CR) subcarriers, while simultaneously assigning subcarrier
pairs for secondary users (SU) and the cognitive relay. This problem is cast as
a constrained optimization problem with constraints on (1) interference
introduced by the SU and the cognitive relay to the PUs; (2) miss-detection and
false alarm probabilities and (3) subcarrier pairing for transmission on the SU
transmitter and the cognitive relay and (4) minimum Quality of Service (QoS)
for each CR subcarrier. We propose one optimal and two sub-optimal schemes all
of which are compared to other schemes in the literature. Simulation results
show that the proposed schemes achieve significantly higher throughput than
other schemes in the literature for different relay situations.Comment: EAI Endorsed Transactions on Wireless Spectrum 14(1): e4 Published
13th Apr 201
Critical Analysis of Solutions to Hadoop Small File Problem
Hadoop big data platform is designed to process large volume of data Small file problem is a performance bottleneck in Hadoop processing Small files lower than the block size of Hadoop creates huge storage overhead at Namenode s and also wastes computational resources due to spawning of many map tasks Various solutions like merging small files mapping multiple map threads to same java virtual machine instance etc have been proposed to solve the small file problems in Hadoop This survey does a critical analysis of existing works addressing small file problems in Hadoop and its variant platforms like Spark The aim is to understand their effectiveness in reducing the storage computational overhead and identify the open issues for further researc
Eddy Current Testing of Zircaloy Wires
Fuel bundles for Rajasthan Atomic Power Reactor, consist of a cluster of 19 elements held together by zir-caloy and plates and spaced by wire helices on the six elements of the inner ring and alternative elements of the outer ring. As in the case of all other reactor mater-ials, the zircaloy wire also need be inspected 100% to avoid any defective part entering the reactor system. The zircaloy wire must be free from defects such as seams, internal voids, welded spots etc apart from the dimensio-nal and metallurgical requirements
A Study on Serum Prolactin Levels in CKD Patients and it’s Correlation with Coronary Artery Heart Disease
BACKGROUND:
In CKD patient’s prolactin clearance & production are altered; this causes Hyperprolactinemia in CKD patients.
CKD is associated with increased risk of CAHD.Emerging evidence suggests that prolactin plays a major role in atherosclerotic process.
OBJECTIVES:
1. To study the occurrence of Hyperprolactinemia in CKD patients.
2. To study the links between hyperprolactinemia in CKD patients & occurrence of CAHD in them.
METHODOLOGY:
We conducted an observational study in 50 CKD patients. Fasting serum prolactin levels were measured in them; Incidence of CAHD was evaluated in them using ECG & ECHO.
RESULTS:
In our study among the 50 CKD patients, 28 patients had Hyperprolactinemia which is about 56% of the study population. Statistical analysis using T test
showed significant association to exist between Hyperprolactinemia & CKD. In our study among the 28 CKD patients with Hyperprolactinemia 17 patients were
diagnosed to have CAHD; this is about 60.7%. Statistical analysis using Chi Square test showed significant association to exist between Hyperprolactinemia in
CKD patients & Occurence of CAHD among them.
CONCLUSION:
Serum prolactin levels are increased in patients with CKD.
This hyperprolactinemia in CKD patients is associated with increased risk of CAHD in them
Application of Time Series Modelling for Predicting the Export Potential of Indian Leather Footwear
Indian leather industry plays a vital role in contributing towards Indian economy. Also it is the core strength of the Indian footwear industry.  According to the Indian leather industry about 37% of the total leather export value is from leather footwear. This shows the importance of studying the trends in leather footwear export, to assist in decision making process. This article proposes a time series model based on monthly export values of leather footwear from India during January, 1999 to March, 2013. In this article based on the information criterion, we identified ARIMA (1, 1, 1) (1, 2, 2) model as a reasonable model to predict the export values of leather footwear from India. This proposed model is used to forecast the export values of leather footwear for the year 2013 – 2014. Keywords: AIC, BIC, leather footwear export, forecast, SARIMA model, time serie
Eddy Current Testing of Zirconium Wires
FUEL bundles for Rajasthan Atomic Power Reactor, as per the design, consist of a cluster of 19 elements held together by zircaloy end plates and spaced by wire
helices on the six elements of the inner ring and alte-rnate elements of the outer ring. Each element is a zircaloy-2 tube 495 min long,1524 mm in diameter and of 0.4 nom wall thickness containing the nuclear fuel in
the form of sintered uranium dioxide pellets and sealed
at both ends. In order to provide the required spacing between the elements, zircaloy wire of 1.25 mm dia. is spot-welded around the elements in the helix form. The wire helices serve to separate the elements to maintain the dimensions of the coolant sub-channels between them
and to increase the mixing of coolant between inner and
outer sub-channels. Zircaloy wire of 1.63 mm dia. is
spot-welded on the outer elements so as to provide
bearing surfaces for the bundle when it moves through
the fuel channels in the coolant assemblies
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